I have a V2 with original sx core installed, I don't use sxos on it these days. Any reason it would be a bad idea to load the latest firmware 0.7.1? Any weird issues with it on the original chips?
The only extra step they list is cleanup option, but I don't think selecting that is going to make the usb start working.Iirc if you are flashing spacecraft nx on original tx chips for the first time there are some extra steps, you can check rentry's guide for more details
https://rentry.org/Spacecraft-NX